michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: "use strict";
michael@0: 
michael@0: module.metadata = {
michael@0:   "stability": "unstable"
michael@0: };
michael@0: 
michael@0: // The minimum and maximum integers that can be set as preferences.
michael@0: // The range of valid values is narrower than the range of valid JS values
michael@0: // because the native preferences code treats integers as NSPR PRInt32s,
michael@0: // which are 32-bit signed integers on all platforms.
michael@0: const MAX_INT = 0x7FFFFFFF;
michael@0: const MIN_INT = -0x80000000;
michael@0: 
michael@0: const {Cc,Ci,Cr} = require("chrome");
michael@0: 
michael@0: const prefService = Cc["@mozilla.org/preferences-service;1"].
michael@0:                 getService(Ci.nsIPrefService);
michael@0: const prefSvc = prefService.getBranch(null);
michael@0: const defaultBranch = prefService.getDefaultBranch(null);
michael@0: 
michael@0: function Branch(branchName) {
michael@0:   function getPrefKeys() {
michael@0:     return keys(branchName).map(function(key) {
michael@0:       return key.replace(branchName, "");
michael@0:     });
michael@0:   }
michael@0: 
michael@0:   return Proxy.create({
michael@0:     get: function(receiver, pref) {
michael@0:       return get(branchName + pref);
michael@0:     },
michael@0:     set: function(receiver, pref, val) {
michael@0:       set(branchName + pref, val);
michael@0:     },
michael@0:     delete: function(pref) {
michael@0:       reset(branchName + pref);
michael@0:       return true;
michael@0:     },
michael@0:     has: function hasPrefKey(pref) {
michael@0:       return has(branchName + pref)
michael@0:     },
michael@0:     getPropertyDescriptor: function(name) {
michael@0:       return {
michael@0:         value: get(branchName + name)
michael@0:       };
michael@0:     },
michael@0:     enumerate: getPrefKeys,
michael@0:     keys: getPrefKeys
michael@0:   }, Branch.prototype);
michael@0: }
michael@0: 
michael@0: function get(name, defaultValue) {
michael@0:   switch (prefSvc.getPrefType(name)) {
michael@0:   case Ci.nsIPrefBranch.PREF_STRING:
michael@0:     return prefSvc.getComplexValue(name, Ci.nsISupportsString).data;
michael@0: 
michael@0:   case Ci.nsIPrefBranch.PREF_INT:
michael@0:     return prefSvc.getIntPref(name);
michael@0: 
michael@0:   case Ci.nsIPrefBranch.PREF_BOOL:
michael@0:     return prefSvc.getBoolPref(name);
michael@0: 
michael@0:   case Ci.nsIPrefBranch.PREF_INVALID:
michael@0:     return defaultValue;
michael@0: 
michael@0:   default:
michael@0:     // This should never happen.
michael@0:     throw new Error("Error getting pref " + name +
michael@0:                     "; its value's type is " +
michael@0:                     prefSvc.getPrefType(name) +
michael@0:                     ", which I don't know " +
michael@0:                     "how to handle.");
michael@0:   }
michael@0: }
michael@0: exports.get = get;
michael@0: 
michael@0: function set(name, value) {
michael@0:   var prefType;
michael@0:   if (typeof value != "undefined" && value != null)
michael@0:     prefType = value.constructor.name;
michael@0: 
michael@0:   switch (prefType) {
michael@0:   case "String":
michael@0:     {
michael@0:       var string = Cc["@mozilla.org/supports-string;1"].
michael@0:                    createInstance(Ci.nsISupportsString);
michael@0:       string.data = value;
michael@0:       prefSvc.setComplexValue(name, Ci.nsISupportsString, string);
michael@0:     }
michael@0:     break;
michael@0: 
michael@0:   case "Number":
michael@0:     // We throw if the number is outside the range or not an integer, since
michael@0:     // the result will not be what the consumer wanted to store.
michael@0:     if (value > MAX_INT || value < MIN_INT)
michael@0:       throw new Error("you cannot set the " + name +
michael@0:                       " pref to the number " + value +
michael@0:                       ", as number pref values must be in the signed " +
michael@0:                       "32-bit integer range -(2^31) to 2^31-1.  " +
michael@0:                       "To store numbers outside that range, store " +
michael@0:                       "them as strings.");
michael@0:     if (value % 1 != 0)
michael@0:       throw new Error("cannot store non-integer number: " + value);
michael@0:     prefSvc.setIntPref(name, value);
michael@0:     break;
michael@0: 
michael@0:   case "Boolean":
michael@0:     prefSvc.setBoolPref(name, value);
michael@0:     break;
michael@0: 
michael@0:   default:
michael@0:     throw new Error("can't set pref " + name + " to value '" + value +
michael@0:                     "'; it isn't a string, integer, or boolean");
michael@0:   }
michael@0: }
michael@0: exports.set = set;
michael@0: 
michael@0: function has(name) {
michael@0:   return (prefSvc.getPrefType(name) != Ci.nsIPrefBranch.PREF_INVALID);
michael@0: }
michael@0: exports.has = has;
michael@0: 
michael@0: function keys(root) {
michael@0:   return prefSvc.getChildList(root);
michael@0: }
michael@0: exports.keys = keys;
michael@0: 
michael@0: function isSet(name) {
michael@0:   return (has(name) && prefSvc.prefHasUserValue(name));
michael@0: }
michael@0: exports.isSet = isSet;
michael@0: 
michael@0: function reset(name) {
michael@0:   try {
michael@0:     prefSvc.clearUserPref(name);
michael@0:   }
michael@0:   catch (e) {
michael@0:     // The pref service throws NS_ERROR_UNEXPECTED when the caller tries
michael@0:     // to reset a pref that doesn't exist or is already set to its default
michael@0:     // value.  This interface fails silently in those cases, so callers
michael@0:     // can unconditionally reset a pref without having to check if it needs
michael@0:     // resetting first or trap exceptions after the fact.  It passes through
michael@0:     // other exceptions, however, so callers know about them, since we don't
michael@0:     // know what other exceptions might be thrown and what they might mean.
michael@0:     if (e.result != Cr.NS_ERROR_UNEXPECTED) {
michael@0:       throw e;
michael@0:     }
michael@0:   }
michael@0: }
michael@0: exports.reset = reset;
michael@0: 
michael@0: function getLocalized(name, defaultValue) {
michael@0:   let value = null;
michael@0:   try {
michael@0:     value = prefSvc.getComplexValue(name, Ci.nsIPrefLocalizedString).data;
michael@0:   }
michael@0:   finally {
michael@0:     return value || defaultValue;
michael@0:   }
michael@0: }
michael@0: exports.getLocalized = getLocalized;
michael@0: 
michael@0: function setLocalized(name, value) {
michael@0:   // We can't use `prefs.set` here as we have to use `getDefaultBranch`
michael@0:   // (instead of `getBranch`) in order to have `mIsDefault` set to true, here:
michael@0:   // http://mxr.mozilla.org/mozilla-central/source/modules/libpref/src/nsPrefBranch.cpp#233
michael@0:   // Otherwise, we do not enter into this expected condition:
michael@0:   // http://mxr.mozilla.org/mozilla-central/source/modules/libpref/src/nsPrefBranch.cpp#244
michael@0:   defaultBranch.setCharPref(name, value);
michael@0: }
michael@0: exports.setLocalized = setLocalized;
michael@0: 
michael@0: exports.Branch = Branch;
michael@0: